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Java Applet Library "MEW.JAR" 
 
FP Web-Server V2.11 
158 
14.1  Introduction to FP Web-Server and the Java Applet 
"MEW.JAR" 
Enhance your HTML Pages with Java Applet Windows: 
The Java Applet technology can be used for complex, 
high-speed, dynamic PLC data visualization in Internet 
Browser windows. Java applets can help to improve your 
HTML pages. You only need standard software, the 
MEW.JAR Java Applet Library and minimal HTML design 
knowledge. 
General: 
Java Applets are user application programs written in the 
programming language Java. These programs are stored 
together with the HTML files in the Http-Server section on the 
FP Web-Server unit. The Java Applet file has the file 
extension .JAR (Java Archive). An Internet browser and a 
special tag within your HTML page are needed to download 
the .JAR to the computer. The Java Applet program is then 
started by the Internet browser and runs on the computer in a 
secure area ('Sandbox'). Each Java Applet has its own 
window which can be freely resized and positioned within 
your HTML page. Parameters within the HTML page can be 
used to configure the Java Applet functions. 
 
Java Applets Compared to HTML and Java Script: 
Normally web pages are designed by using HTML and Java Script (DHTML) code, which allow 
only very limited dynamic features to be implemented. Moreover, DHTML is not very fast and is 
not compatible with the various Internet browsers. The programming language Java, which is 
used to design Java Applets, is a powerful, future-oriented tool for programming huge 
applications. Java code can run on various computer systems, e.g. Linux and Solaris. Java 
code runs in a separate, secure area and hence cannot compromise the computer. 
The Java Runtime System: 
Java program code cannot be executed directly by the computer's CPU (Windows, Linux, 
Solaris...). Java code is a kind of intermediate or meta code and needs a special software to be 
interpreted and executed. The required Java interpreter software from the company SUN is 
called 'Java 2 Runtime Environment', or in short 'JRE'. 
 
For more information on the Java Applet Library, please refer to the online help under 
the keyword "Java Applet Library" or to the pdf file "JavaAppletLibrary.pdf" on your 
installation CD-ROM in the sub-folder "JavaApplets".